Page 8 - Journal of Structural Heart Disease Volume 2, Issue 1

Review Article
2
decreasing the associated mortality from stroke [10]. In clinical practice however, patients who are warfarin eligible are often not treated [11]. In addition, approx- imately a quarter of patients who initiate therapy will discontinue its use at 1 year [12]. Novel oral antico- agulants (NOAC) have been shown to be non-inferior or superior compared to warfarin but also have dis- continuation rates of between 17–25% at 2 years [13- 15]. Complications from anticoagulation, including bleeding, intolerance, and falls, present challenges to traditional therapy and NOACs alike.
The left atrial appendage (LAA) is known play a sig- ni cant role in thrombus formation and stroke in AF, with approximately 90% of thrombi located in the LAA in patients with nonvalvular AF based on echo- cardiographic and autopsy data [16]. Percutaneous LAA closure has emerged as an alternative strategy for reducing risk of thromboembolic stroke in patients with nonvalvular AF. Understanding the history of LAA closure and the emergence of current percutaneous technologies is imperative to the understanding of the developing eld and future indications.
The Left Atrial Appendage
The LAA is a complex structure that is a remnant of the embryological left atrium. This pouch-like projection has a variety of morphologic appearanc- es and anatomy with variable size, length, width,
Table 1: CHADS2 and CHA2DS2-VASC for ischemic stroke
and number of lobes. In the setting of AF, poor atri- al transport function results in stasis within the LAA. This can be documented by low Doppler in ow ve- locities on transesophageal echocardiography (TEE) and by spontaneous echo contrast, which are both associated with increased risk of stroke [17]. The walls can have a signi cant amount of trabecula- tions which may predispose to stroke [18]. Four main morphologies have been characterized based on ap- pearance including: chicken wing, cactus, wind sock, and cauli ower. Non-chicken wing morphologies are signi cantly more likely to be associated with a thromboembolic event [19] even after controlling for traditional risk factors (CHADS2 score.) Other factors such as endothelial dysfunction, in ammation, plate- let activation, and hypercoagulable state have also been implicated in having a role the increased risk of thromboembolism [20, 21]. Assessment of stroke risk in AF remains of paramount importance. Utilization of the CHADS2 score previously and now CHA2DS2VASc score [22] is recommended to determine patient risk per year of stroke and subsequent need for possible anticoagulation (Table 1).
Oral anticoagulation utilizes a systemic approach to decrease thrombus formation and subsequent thromboembolism. In contrast, LAA closure provides a local therapy to achieve a similar result. LAA closure is especially appealing in patients intolerant or with contraindications to systemic anticoagulation.
CHADS2
CHA2DS2-VASC
C H A D S2
Maximum score
6
V Vascular disease 1 A Age 65–74 years 1 Sc Sex (female gender) 1
9
Risk Factor
Congestive heart failure Hypertension
Age 75 years
Diabetes mellitus Previous stroke or TIA
Points
1 C 1 H 1 A2 1 D 2 S2
Risk Factor
Congestive heart failure 1 Hypertension 1 Age 75 years 2 Diabetes mellitus 1 Previous stroke or TIA 2
Points
Journal of Structural Heart Disease, February 2016
Volume 2, Issue 1:1-14